3 Answers
3

He is a lifelong sufferer of Obsessive-Compulsive Disorder and has
many phobias, and those obsessions became crippling after his
breakdown, forcing his retirement; he recovers throughout the series,
though he is never fully "cured". His OCD is also the reason Monk was
such a successful policeman; one of his compulsions is paying amazing
attention to details.

Unless in the last four episodes they addressed this, then no it wasn't. However, I'm not sure how much monk you have actually seen, but his OCD seems to get worse as the show progresses. My theory is that he wasn't as bad when he was younger, so getting through police academy wouldn't have been as hard. But that's just my theory

Adrian Monk was a very brilliant detective for the SFPD until he had a nervous breakdown due to his wife's death in the car bomb blast. He gradually started living in voluntary seclusion and was discharged from the police department. He finally was able to come out of seclusion after three and a half years with the help of nurse Sharona Fleming and this also enabled him to become a private investigator/detective.

My assumption is that the massive nervous breakdown was one of the key reasons of all his fear, phobias and disorders.